What is the purpose of securing a crime scene and establishing a perimeter?

• A. To maximize the number of witnesses who can observe the area.
• B. To preserve evidence, prevent contamination, and protect safety of the public and responders.
• C. To allow unrestricted access for all personnel.
• D. To delay the investigation to a later shift.

Answer: (B)

Securing a crime scene and establishing a perimeter is about preserving evidence and ensuring safety by controlling access. When access is limited to authorized personnel, the chance of evidence being altered, damaged, or contaminated drops dramatically. The established boundary defines a controlled zone where investigators can document, collect, and analyze traces without external interference, helping maintain a clear chain of custody as items move from the scene to the lab. This approach also protects the public and responders from hazards present at the site.

Keeping the scene open to many witnesses or unrestricted personnel would increase contamination and confusion, while delaying the investigation would allow potential evidence to degrade or be lost.